U.S. patent application number 11/585136 was filed with the patent office on 2007-04-26 for substrate cleaning apparatus.
Invention is credited to Yoshiharu Yamamoto.
Application Number | 20070089767 11/585136 |
Document ID | / |
Family ID | 37984218 |
Filed Date | 2007-04-26 |
United States Patent
Application |
20070089767 |
Kind Code |
A1 |
Yamamoto; Yoshiharu |
April 26, 2007 |
Substrate cleaning apparatus
Abstract
An apparatus for cleaning a whole substrate by ejecting a
cleaning liquid from a nozzle while rotating the substrate, the
apparatus comprising: two or more linear reciprocating driving
sources capable of generating outputs independently of one another;
a rotation shaft; two or more cam mechanisms for converting the
outputs into rotating forces; two or more sets of rotation columns
fixed to the rotation shaft rotatably about their respective axes
to horizontally support the substrate and sandwich or release the
side surface of the substrate in cooperation with one another along
with their rotation; two or more transfer members capable of
transferring the rotating force to the sets of rotation columns in
conjunction with the cam mechanisms, respectively; and a stopper
causing the rotation of the cam mechanisms to be related to the
rotation of the rotation shaft.
Inventors: |
Yamamoto; Yoshiharu; (Shiga,
JP) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Family ID: |
37984218 |
Appl. No.: |
11/585136 |
Filed: |
October 24, 2006 |
Current U.S.
Class: |
134/149 ;
134/137 |
Current CPC
Class: |
B08B 3/02 20130101; H01L
21/68728 20130101; H01L 21/67051 20130101 |
Class at
Publication: |
134/149 ;
134/137 |
International
Class: |
B08B 3/00 20060101
B08B003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 25, 2005 |
JP |
2005-309597 |
Sep 15, 2006 |
JP |
2006-250697 |
Claims
1. An apparatus for cleaning a substrate by ejecting a cleaning
liquid from a nozzle while rotating the substrate, the apparatus
comprising: a main body; two or more linear reciprocating driving
sources mounted to the main body, the driving sources being capable
of generating outputs independently of one another; a rotation
shaft rotatably mounted to the main body; two or more cam
mechanisms mounted to the main body rotatably about the rotation
shaft, the cam mechanisms being for converting the outputs into
rotating forces; two or more sets of rotation columns having
respective axes parallel to the rotation shaft at positions
radially spaced from the center of the rotation shaft, the rotation
columns being fixed to the rotation shaft rotatably about their
respective axes to horizontally support the substrate and sandwich
or release the side surface of the substrate in cooperation with
one another along with their rotation; two or more transfer members
having a rotation center concentric with the rotation shaft, the
transfer members being capable of transferring the rotating force
to the sets of rotation columns in conjunction with the cam
mechanisms, respectively; and a stopper secured to the rotation
shaft and causing the rotation of the cam mechanisms to be related
to the rotation of the rotation shaft.
2. The apparatus according to claim 1, wherein the rotation columns
include a column having an upper surface and a pin erected at a
decentered position on the upper surface and brought into contact
with the side surface of the substrate or separated therefrom along
with the rotation of the column, and the pins constituting each set
are placed substantially at even intervals in the circumferential
direction and are placed at phase positions different from the
other sets of pins.
3. The apparatus according to claim 2, wherein the upper surface is
inclined and the decentered position is a highest position on the
upper surface.
4. The apparatus according to claim 1, wherein gear teeth are
formed on the outer peripheral surfaces of the rotation columns and
on the outer peripheral surfaces of the transfer members, such that
the gear teeth formed on the outer peripheral surfaces of the
rotation columns and the gear teeth formed on the outer peripheral
surfaces of the transfer members are engageble with each other.
5. The apparatus according to claim 1, wherein the cam mechanisms
are constituted by a grooved cam which is mounted rotatably with
respect to the main body and movably in the direction of the
rotation shaft and has a groove inclined with respect to the
rotation shaft, and a roller which rotates within the groove and is
mounted to the corresponding transfer member.
6. The apparatus according to claim 5, wherein the stopper is a
disk member orthogonal to the rotation shaft and has concave
portions which allow the grooved cams to move in the direction of
the rotation shaft and cause the grooved cams to rotate together
with the rotation shaft.
7. The apparatus according to claim 1, further comprising a table
secured to the upper end of the rotation shaft, wherein the
rotation columns are hermetically fixed to the rotation shaft
through the table.
8. An apparatus for cleaning a substrate by ejecting a cleaning
liquid from a nozzle while rotating the substrate, the apparatus
comprising: a main body; two or more linear reciprocating driving
sources mounted to the main body, the driving sources being capable
of generating outputs independently of one another; a rotation
shaft rotatably mounted to the main body; a table secured to the
upper end of the rotation shaft; two or more cam mechanisms mounted
to the main body rotatably about the rotation shaft, the cam
mechanisms being for converting the outputs into rotating forces;
two or more sets of rotation columns having respective axes
parallel to the rotation shaft at positions radially spaced from
the center of the rotation shaft, the rotation columns being
hermetically fixed to the table rotatably about their respective
axes to horizontally support the substrate and sandwich or release
the side surface of the substrate in cooperation with one another
along with their rotation; two or more transfer members having a
rotation center concentric with the rotation shaft, the transfer
members being capable of transferring the rotating force to the
sets of rotation columns in conjunction with the cam mechanisms,
respectively; a stopper secured to the rotation shaft and causing
the rotation of the cam mechanisms to be related to the rotation of
the rotation shaft; and a cover capable of being hermetically
contacted with the upper surface of the table and housing the
rotation columns.
9. The apparatus according to claim 8, wherein the rotation shaft
has a tubular shape, a center shaft is fitted within the rotation
shaft, a cleaning-liquid supply pipe is inserted through the center
shaft, the lower end of the center shaft is secured to the main
body and the upper end of the center shaft is penetrated through
the table while maintaining the hermeticity.
10. The according to claim 1, wherein the transfer members are made
of a resin and are in contact with the rotation shaft such that the
transfer members are rotatable together with the rotation
shaft.
11. The apparatus according to claim 1, wherein the transfer
members are made of a metal and are fitted with the rotation shaft
through a bearing.
Description
TECHNICAL FIELD
[0001] The present invention relates to an apparatus capable of
cleaning the surface, the back surface and the outer peripheral
surface of a substrate and can be preferably used for cleaning a
precision substrate, such as a semiconductor substrate, a liquid
crystal glass substrate, a mask substrate.
BACKGROUND ART
[0002] As an apparatus for cleaning a substrate, there has been
conventionally known an apparatus as illustrated in FIG. 11 (for
example, JP-A No. 8-299918). The apparatus 101 basically includes a
table 102 for holding a substrate 150 by sucking the back surface
thereof with a vacuum pump which is not illustrated, a motor 125
for rotating the table 102 with respect to the apparatus main body,
and a cleaning-liquid ejecting nozzle which can be revolved above
the table 102.
[0003] Further, a cleaning liquid is ejected from the ejection
nozzle for cleaning the surface of the substrate 150, while the
ejection nozzle is reciprocated in the radial direction of the
table 102 with respect to the substrate 150 being rotated along
with the table 102. During the cleaning, the substrate 150 is
surrounded by a cover 110, thereby preventing the cleaning liquid
from scattering. When the back surface is cleaned, the evacuation
is temporarily stopped, and an operator reverses the substrate 150
with his or her power using gloves, or extracts the substrate 150
on a carrying-out table 161, reverses it with a reversing device
(for example, JP-A No. 2003-7663), then introduces it into the
apparatus main body on a carrying-in table 160 and performs the
cleaning operation, again. When carrying out and carrying in, the
cover 110 is pushed up to the upper withdrawal position with an air
cylinder 131.
[0004] As another conventional apparatus for cleaning a substrate,
there has been suggested an apparatus which holds a substrate at
the peripheral edge of a table having a center concave portion,
places a lower nozzle within the concave portion and supplies a
cleaning liquid to the lower nozzle through a pipe passing through
the rotation shaft of the table (JP-A No. 11-156314). This
apparatus can clean the back surface of the substrate with the
cleaning liquid ejected from the lower nozzle, thereby eliminating
the necessity of reversing the substrate. Further, although JP-A
No. 11-156314 describes no means for securing the substrate on the
table, it can be perceived, from the configuration illustrated in
the figure, that the peripheral edge of the substrate is held by
the table at plural positions individually.
[0005] Both the apparatuses employ, in order to dry the substrate
after cleaning, a method of increasing the rotation speed to about
three times the rotation speed during cleaning for throwing off the
cleaning liquid or, in some cases, employ a method of ejecting an
alcohol such as isopropyl alcohol (IPA) to the substrate for
reducing the drying time.
[0006] However, in performing cleaning, the conventional cleaning
apparatus illustrated in FIG. 11 requires a longer time period to
reverse the substrate 150, thereby reducing the cleaning
efficiency. Further, since the apparatus temporarily stops the
rotation of the substrate before reversing it, in the case where
the substrate is a printed circuit board, a conductive material may
be scattered due to the pressure of the cleaning liquid and adhered
to the surface and the back surface of the substrate, thereby
contaminating the substrate, during the stoppage of the substrate.
In the case where the conductive material is made of a
low-resistance material such as copper, even a small amount of such
a conductive material adhered to the substrate may induce
short-circuits between wirings, thus reducing the yield of
products. Further, it is difficult to clean the outer peripheral
surface of the substrate. The apparatus disclosed in JP-A No.
11-156314 holds the peripheral edge of the substrate with the table
at plural positions individually, which makes it difficult to
attach or detach the substrate to or from the table.
[0007] Next, regarding drying, when the aspect ratios of wiring
trenches (grooves) are larger, water marks or IPA may be left in
the trenches, which may cause corrosion or contamination of the
conductive material, thereby increasing the electric resistances.
In some cases, secondary contaminations may occur due to robot
hands and the like. This makes it necessary to provide sufficient
measures for preventing combustion of the alcohol.
DISCLOSURE OF THE INVENTION
[0008] Therefore, it is an object of the present invention to
provide an apparatus capable of cleaning the outer peripheral
surface of a substrate while rotating the substrate. It is another
object to provide an apparatus capable of cleanly drying a
substrate after cleaning of the substrate.
[0009] In order to attain the objects, according to the present
invention, there is provided an apparatus for cleaning a substrate
by ejecting a cleaning liquid from a nozzle while rotating the
substrate, wherein the cleaning apparatus comprises a main body,
two or more linear reciprocating driving sources capable of
generating outputs independently of one another, a rotation shaft
rotatably mounted to the main body, two or more cam mechanisms, two
or more sets of rotation columns, two or more transfer members and
a stopper.
[0010] The cam mechanisms are mounted to the main body such that
they are rotatable about the rotation shaft and convert the
aforementioned outputs into rotating forces. The rotation columns
have respective axes parallel to the rotation shaft at positions
radially spaced from the center of the rotation shaft and are fixed
to the rotation shaft rotatably about their axes to horizontally
support a substrate and sandwich or release the side surface of the
substrate in cooperation with one another, along with rotation
thereof. The transfer members have a rotation center which is
concentric with the rotation shaft and transfer the aforementioned
rotating forces to the sets of the rotation columns in conjunction
with the cam mechanism. The stopper is secured to the rotation
shaft and causes the rotation of the cam mechanism to be related to
the rotation of the rotation shaft.
[0011] The apparatus according to the present invention has effects
as follows. At first, a substrate is supported by the rotation
columns and is sandwiched by one set of rotation columns (which is
referred to as a set A and another set is referred to as a set B),
out of the plural sets of rotation columns, while the rotation
shaft is rotated. Consequently, the substrate is rotated, thereby
enabling cleaning the substrate by ejecting a cleaning liquid
thereto. At this stage, it is possible to clean the whole substrate
except for the portions of the outer peripheral surface of the
substrate which are in contact with the set A of the rotation
columns. During this time, the transfer members and the cam
mechanisms are also rotated together with the rotation shaft along
with the stopper and, also, the respective rotation columns are
revolved about a center axis which passes through the rotation
shaft.
[0012] Next, an output is generated from a driving source to rotate
the set B of rotation columns through one of the cam mechanisms and
one of the transfer members along a transfer path from the driving
source to the set B of the rotation columns. Namely, the cam
mechanism converts the output of the driving source into a rotating
force and the rotating force is transferred to the set B of
rotation columns through the transfer member. Along therewith, the
set B of rotation columns being revolved are rotated about their
axes. This causes the substrate to be sandwiched by the set B of
rotation columns as well as the set A of rotation columns.
[0013] Thereafter, the direction of the output from another driving
source is changed to rotate the set A of rotation columns about
their axes. Consequently, the substrate is released from the set A.
This enables cleaning the portions which have been contacted with
the set A of rotation columns and thus have been left
uncleaned.
[0014] The aforementioned rotation columns may include a column
having an upper surface, and a pin which is erected at a decentered
position on the upper surface and is brought into contact with the
side surface of the substrate or separated therefrom along with the
rotation of the column, because the bottom surface of the substrate
can be supported by the upper surfaces of the columns while the
side surface of the substrate can be sandwiched by the pins or
released therefrom without damaging the side surface. In this case,
the respective sets of pins are placed, such that the pins
constituting each set are placed at substantially even intervals in
the circumferential direction and are placed at phase positions
different from the other sets of pins. Consequently, the respective
sets of pins can alternately sandwich or release the substrate. In
this configuration of the rotation columns, it is preferable that
the aforementioned upper surfaces are inclined and the
aforementioned decentered positions are the highest positions on
the upper surfaces. This causes the upper surfaces to be contacted
with the bottom surface of the substrate in a point-to-point
contact, which allows the cleaning liquid to easily pass between
the upper surfaces and the bottom surface of the substrate, thereby
further improving the cleaning effect.
[0015] The means for transferring the rotating force from the
transfer members may be gear transmission and belt transmission. It
is desirable to employ gear transmission, namely it is desirable to
form gear teeth on the outer peripheral surfaces of the
aforementioned rotation columns and form gear teeth on the outer
peripheral surfaces of the transfer members such that these gear
teeth are engageble with each other.
[0016] The aforementioned cam mechanisms may be combinations of a
grooved cam having a groove inclined with respect to the rotation
shaft which is mounted rotatably with respect to the main body and
movably in the direction of the rotation shaft and a roller which
rotates within the groove and is secured to the corresponding
transfer member. Since the groove is inclined with respect to the
rotation shaft, the movement of the grooved cam in the direction of
the rotation shaft displaces the roller in the circumferential
direction, thereby rotating the transfer member.
[0017] The aforementioned stopper may be a disk member which is
orthogonal to the rotation shaft and has concave portions which
allow the grooved cams to move in the direction of the rotation
shaft and cause the grooved cams to rotate together with the
rotation shaft.
[0018] It is preferable that a table is secured to the upper end of
the aforementioned rotation shaft and the aforementioned rotation
columns are hermetically secured to the rotation shaft through the
table, because components under the table can be prevented from
being wetted. Further, it is preferable that the table extends
outwardly in the radial direction from the rotation columns and
there is provided a cover which can be hermetically contacted with
the upper surface of the extended portion of the table and can
house the rotation columns. This can house the substrate within an
extremely narrow sealed space. This enables rapidly drying the
substrate while halting the substrate at the position, by combining
depressurization means and means for introducing a gas inert to the
substrate material. Further, such a hermetic sealing configuration
using a table and rotation columns can be applied to cleaning
apparatus having, under a table, power transfer mechanisms
different from that of the present invention.
[0019] Namely, in order to attain the aforementioned second object,
a preferable substrate drying apparatus includes a table, plural
supporting columns erected between the center of the table and the
peripheral edge thereof for supporting a substrate (in the case
where the aforementioned cleaning apparatus is a compound apparatus
which also serves as the drying apparatus, the rotation columns
form the supporting columns), a cover which can be hermetically
contacted with the upper surface of the table to house the
supporting columns and is movable in such a direction that it is
separated from the table, and means for depressurizing the space
surrounded by the cover which is contacted with the table and the
table.
[0020] The substrate cleaning apparatus according to the present
invention can clean an entire substrate including its outer
peripheral surface while rotating the substrate. This can alleviate
adhesion of a conductive material scattered due to the pressure of
the cleaning liquid to the substrate, thereby improving the
cleanliness of the cleaned substrate. Further, the entire apparatus
has a smaller size, since there is provided no
reversing/transferring devices for cleaning the surface and the
back surface of a substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is an axial cross-sectional view illustrating a
cleaning apparatus according to a first embodiment.
[0022] FIG. 2 is a plan view illustrating main bodies of the same
cleaning apparatus.
[0023] FIG. 3 is a front view illustrating a grooved cam in the
same cleaning apparatus.
[0024] FIGS. 4A and 4B are a plan view and a front view
illustrating the relationship between a grooved cam and a stopper
in the same cleaning apparatus, respectively.
[0025] FIGS. 5A and 5B are a plan view and a rear view illustrating
the relationship between another grooved cam and the stopper in the
same cleaning apparatus, respectively.
[0026] FIG. 6 is a plan view illustrating a transfer member in the
same cleaning apparatus.
[0027] FIG. 7 is a plan view illustrating another transfer member
in the same cleaning apparatus.
[0028] FIG. 8 is a view illustrating the timing of rotations of a
set of rotation columns and another set of rotation columns.
[0029] FIG. 9 is an axial cross-sectional view illustrating a
cleaning apparatus according to a second embodiment.
[0030] FIG. 10 is an enlarged view of the portion D in FIG. 9.
[0031] FIG. 11 is an axial cross-sectional view illustrating main
parts of a conventional cleaning apparatus.
[0032] FIG. 12 is an axial cross-sectional view illustrating a
modified example of the cleaning apparatus according to the first
embodiment.
[0033] FIG. 13 is an axial cross-sectional view illustrating a
modified example of the cleaning apparatus according to the second
embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] Embodiments of the present invention will be described with
reference to the drawings.
First Embodiment
[0035] FIG. 1 is an axial cross-sectional view illustrating a
cleaning apparatus according to a first embodiment and FIG. 2 is a
main-part plan view of the same.
[0036] The cleaning apparatus 1 is configured to eject a cleaning
liquid while rotating a semiconductor substrate 70 to clean the
semiconductor substrate 70. The cleaning apparatus 1 includes a
main body 43 having a cylindrical portion, a driving motor 9
secured to the main body 43, a hollow rotation shaft 4 mounted via
upper and lower bearings 30 to the inner peripheral surface of the
cylindrical portion of the main body 43, three reciprocating air
cylinders 51 secured through a cylinder base 46 to the main body 43
at even intervals in the circumferential direction, and three
reciprocating air cylinders 52 similarly secured through a cylinder
base 47. The driving motor 9 rotates the rotation shaft 4 about its
axis through a belt. A disk-shaped table 3 is fastened to the upper
end of the rotation shaft 4 with bolts. A center shaft 5 is fitted
within the rotation shaft 4 through upper and lower bearings 7, and
two cleaning-liquid supply pipes are passed through the center
shaft 5. The center shaft 5 is protruded upwardly from the table 3,
and two lower nozzles 6 connected to the respective supply pipes
are mounted to the upper end of the center shaft 5, and the lower
end of the center shaft 5 is secured to the main body 43.
[0037] The two sets of air cylinders 51 and 52 include rods which
reciprocate in the upward and downward directions along with blocks
56 and 57 provided at their tip ends and are connected to a control
device, which is not illustrated, such that the cylinders
constituting each set operate in synchronization with one another
and generate outputs independently of the other set of cylinders.
An annular grooved cam 37 surrounding the cylindrical portion of
the main body 43 is mounted to the block 57 through a bearing 32,
while another annular grooved cam 36 is mounted to the block 56
through a bearing 31 such that it surrounds the grooved cam 37.
Namely, the grooved cams 36 and 37 are placed in a double ring
shape in a non contact manner. As illustrated in a front view of
FIG. 3, three upward protrusions 40 are formed on the peripheral
edge portion of the grooved cam 36 at even intervals in the
circumferential direction and, further, protrusions 41 are formed
on the peripheral edge portion of the grooved cam 37 at positions
deviated in phase by 60 degrees from the protrusion 40. Further,
grooves 38 and 39 are radially formed through the protrusions 40
and 41, wherein the grooves 38 and 39 are inclined in an
upward-and-leftward direction when viewed from the outside. The
inclination of the groove 38 is smaller than the inclination of the
groove 39, in order to make the rotation stroke of a transfer
member 26 which will be described later equal to the rotation
stroke of a transfer member 27. Above the grooved cams 36 and 37, a
disk-shaped stopper 23 having an outer diameter greater than that
of the grooved cam 36 is protruded in the radial direction from the
outer peripheral surface of the rotation shaft 4. The stopper 23 is
fastened to the rotation shaft 4 with bolts. The stopper 23 has
cutouts 24 and holes 25 for receiving the protrusions 40 and 41
with slight clearance at the positions corresponding to the
protrusions 40 and 41, as illustrated in FIGS. 4A, 4B, 5A and 5B.
This allows upward and downward movements of the grooved cams 36
and 37 and also prevents the rotations of the grooved cams 36 and
37 relative to the rotation shaft 4.
[0038] On the other hand, three rotation columns 10 are mounted to
the peripheral edge of the table 3 at even intervals in the
circumferential direction and, further, rotation columns 11 are
mounted to the same periphery at positions deviated in phase by 60
degrees from the rotation columns 10. The three rotation columns 10
have the same shape. This also applies to the rotation columns 11.
The rotation columns 10 and 11 are rotatably penetrated through the
table 3 in the vertical direction. Further, the upper surfaces of
the rotation columns 10 and 11 are inclined with moderate
gradients, and round-bar-shaped pins 20 and 21 are upwardly
protruded at substantially highest positions of the upper surfaces.
Gears 12 and 13 are fitted and secured to the rotation columns 10
and 11 at their portions under the table 3. These gears 12 and 13
are engaged with gear teeth 28 and 29 formed on the outer
peripheral surfaces of the transfer members 26 and 27,
respectively. The transfer members 26 and 27 have substantially a
disk shape having an axial hole at the center, as illustrated in
plan views of FIGS. 6 and 7. The transfer member 26 is made of a
resin having a low friction coefficient such as a fluororesin and
is slidably fitted to the outer peripheral surface of the rotation
shaft 4 at a position just under the table 3. The transfer member
27 is similarly fitted to the rotation shaft 4 at a position lower
than the transfer member 26. Further, the transfer members 26 and
27 are provided with concave-shaped relieves 71 and 72, in order to
prevent the transfer members 26 and 27 from interacting with the
gears 13 and 12 which are not to be engaged therewith. Further,
near the lower surfaces of the transfer members 26 and 27, rollers
16 and 17 are mounted through brackets such that they are rotatable
within the grooves 38 and 39 of the grooved cams. Further, the
reference character 73 in FIG. 7 designates holes for inserting the
brackets therethrough.
[0039] Above the table, there is provided an upper nozzle (not
illustrated). The upper nozzle is similar to an ejecting device 30
disclosed in WO2005-38893, for example, and is held at an end
portion of an arm, wherein the other end of the arm is connected to
a joint such that it is rotatable about a horizontal axis, and the
joint is rotatably erected on the main body. Accordingly, the upper
nozzle can be moved in the horizontal direction and also can be
inclined and is capable of ejecting the cleaning liquid toward the
upper surface and the side surfaces of the substrate.
[0040] Further, as illustrated in an axial cross-sectional view of
FIG. 12, the transfer members 26 and 27 can be engaged with the
rotation shaft 4, with ball-and-roller bearings 60 and 61
interposed therebetween.
[0041] There will be described the operation for cleaning a
circular substrate 70 using the cleaning apparatus 1. In the
following description, the terms "clockwise direction" and "counter
clockwise direction" refer to "the clockwise direction in a plan
view" and "the counter clockwise direction in a plan view",
respectively. The substrate 70 is placed on the upper surfaces of
the rotation columns 10 and 11, while the motor 9 is kept at an OFF
state, the rotation of the table 3 is kept stopped and the pins 20
and 21 are kept withdrawn outwardly from the outer peripheral
surface of the substrate 70. Then, the block 56 is lowered. This
causes the grooved cam 36 to be lowered along with the block 56.
FIGS. 4A and 4B illustrate a state where the grooved cam 36 has
been lowered. While the grooved cam 36 tries to rotate in the
direction of the groove 38 during the lowering due to the reaction
force from the rollers 16, the stopper 23 prevents the rotation of
the cam 36 by means of the engagement between the protrusions 40
and the cutouts 24. Accordingly, on the contrary, the rollers 16
are moved in the clockwise direction while rotating within the
groove 38 during the lowering of the grooved cam 36 and, along
therewith, the transfer member 26 is rotated in the same direction.
This causes the three rotation columns 10 to be concurrently
rotated in the counter clockwise direction, thereby causing the
three pins 20 to sandwich the outer peripheral surface of the
substrate 70 (FIG. 8(a)). As a result, the substrate 70 is held by
the set of the three rotation columns 10 in such a manner as to
maintain the center of the table 3 and that of the substrate 70
coincident with each other.
[0042] At this state, the motor 9 is driven to cause the substrate
70 to rotate together with the rotation shaft 4 and the table 3,
while a cleaning liquid is ejected from the upper and lower
nozzles. Consequently, the substrate 70 is cleaned substantially
over its entire surface, except the portions thereof which is in
contact with the pins 20. During this time, the transfer members 26
and 27 and the grooved cams 36 and 37 are accompanied by the
stopper 23 and rotated together with the rotation shaft 4, and the
respective rotation columns 10 and 11 are also revolved about the
center shaft 5.
[0043] Next, the block 57 is lowered by means of the cylinder 52.
Then, during lowering the block 56, the grooved cam 37 is lowered
from the ascent position of FIG. 1 in the same way of lowering the
grooved cam 36, and the transfer member 27 is rotated in the
clockwise direction along with the rotation of the rollers 17. This
causes the rotation columns 11 being revolved to be rotated in the
counter clockwise direction, thereby causing the three pins 21 to
sandwich the outer peripheral surface of the substrate 70. As a
result, the substrate 70 is held by the sets of rotation columns
each set being constituted by three rotation columns, namely a
total of six rotation columns, without stopping the rotation of the
substrate 70 (FIG. 8(b)).
[0044] Thereafter, the block 56 is lifted by means of the cylinder
51 along with the grooved cam 36. This causes the transfer member
26 to be rotated in the counter clockwise direction, thereby
causing the rotation columns 10 being revolved to be concurrently
rotated in the clockwise direction. Consequently, the three pins 20
are separated from the substrate 70 (FIG. 8(c)), thereby allowing
its portions which have been contacted with the pins 20 to be
cleaned.
[0045] The cylinders 51 and 52 can be either push-type cylinders or
pull type cylinders. In any of the cases, it is preferable to use
return springs in combination therewith, in order to enable
lowering the blocks 56 and 57 even in the event of stoppage of air
supply due to a power failure, air leakage and the like. Further,
while the numbers of the cylinders 51 and 52, the protrusions 40
and 41 and the rollers 16 and 17 provided therein are all three, in
order to reduce the bending moments to reduce the distortions
generated in the grooved cams, the rollers and the transfer
members, the numbers of them are not limited. The rotation columns
10 and 11 can have horizontal upper surfaces, but it is preferable
that their upper surfaces are inclined. When their upper surfaces
are inclined, the substrate 70 is supported by the rotation columns
10 and 11, in a point-to-point contact. This allows the cleaning
liquid to easily pass between the bottom surface of the substrate
70 and the rotation columns 10 and 11, thereby increasing the
cleaning ability. It is not necessary that the geometrical center
of the table 3 is coincident with the rotation center thereof and,
in the case where they are not coincident with each other, it is
possible to clean the entire surface including the geometrical
center more evenly. In order to make the geometrical center
incoincident with the rotation center, one of the three rotation
columns 10 (and 11) can be engaged with the transfer member 26 (and
27) such that it precedes or delays from the other two rotation
columns by a tooth or two teeth.
Second Embodiment
[0046] FIG. 9 is an axial cross-sectional view illustrating a
substrate cleaning apparatus according to a second embodiment. FIG.
10 is an enlarged view of the portion D in FIG. 9. The cleaning
apparatus according to the present embodiment enables drying a
substrate without moving the substrate, after cleaning. The
cleaning apparatus 2 can have the same configuration as that of the
first embodiment, under the table 3. Hereinafter, there will be
described, in detail, differences from the first embodiment and
portions which were not described in the first embodiment.
[0047] In the present embodiment, a cup-shaped cover 80 capable of
housing the rotation columns 10 and 11 is provided on the upper
surface of the table 3 such that it is hermetically contacted with
the upper surface. The cover 80 can be hoisted and lowered by means
of a hoisting apparatus which is not illustrated. Ring seals 88
made of a rubber or a fluororesin are fitted around the outer
peripheral surfaces of the rotation columns 10 and 11. O-ring seals
89 are similarly fitted around the outer peripheral surfaces of
bolts with which the table 3 is fastened to the rotation shaft 4.
Further, as illustrated in FIG. 10, a ring seal 90 made of a
fluororesin is fitted within an axial hole 30 in the table 3. The
ring seal 90 has a dual-lip shape having lips protruding upwardly
and downwardly from the inner peripheral surface thereof. These
lips are intimately contacted with the outer peripheral surface of
the center shaft 5 and are curved in such directions that they are
gradually separated from each other with decreasing distance from
the center shaft 5. Accordingly, during both pressurizing and
depressurizing, it is possible to prevent air from passing
therethrough. Further, the ring seal 90 is made of a fluororesin
and, thus, has excellent chemical resistance and is less prone to
generate dust. Thus, the hermeticity of the table 3 is maintained.
Further, the table 3 extends to protrude from the rotation columns
10 and 11 outwardly in the radial direction. Further, when the
cover 80 is lowered, the lower end surface of the cover 80 comes
into contact with the upper surface of the protruding portion with
a rubber O-ring seal 87 interposed therebetween. The O-ring seal 87
is fitted in an annular-shaped concave portion 74 formed in the
lower end surface of the cover 80. The cover 80 is provided with
switching valves 82 and 85 and an exhaust valve 86. Accordingly,
when the cover 80 is lowered to be contacted with the table 3, air
is prevented from flowing into and from the space S surrounded by
the cover 80 and the table 3.
[0048] It is also possible to ensure the hermeticity at the portion
where the table 3 and the center shaft 5 are fitted with each
other, by using two or more seals, such as a seal with an upper lip
(for pressurization) and a seal with a lower lip (for
depressurization), instead of using the ring seal 90. As
illustrated in a longitudinal cross-sectional view of FIG. 13, an
annular concave portion 75 can be formed in the upper surface of a
table 3', instead of the concave portion 74, and an O-ring seal 87
can be fitted therein to enable hermetically contacting the upper
surface of the table 3' with the lower end surface of the cover
80'. Further, the enlarged view of the portion D in FIG. 13 is
similar to FIG. 10.
[0049] With the aforementioned cleaning apparatus 2, after the
rotation of the table 3 is stopped and the cover 80 is lowered to
seal the periphery of the substrate 70 with the cover 80 and the
table 3, the pressure can be reduced with a vacuum pump 81 through
the switching valve 82 for drying the substrate 70. By alternating
the sets of the rotation columns 10 and 11 which support the
substrate 70, it is possible to dry the portions contacted with the
columns 10 and 11 without moving the substrate 70. Since the
depressurization increases the vaporization speed of the cleaning
liquid, the substrate 70 is dried at a room temperature.
Furthermore, the space S to be depressurized is a small area
surrounded by the upper surface of the table 3 and the cover 80
and, therefore, can be rapidly depressurized. This can prevent
occurrence of water marks. Furthermore, there is no need for moving
the substrate 70 after cleaning, thereby preventing contaminations
which would occur during moving. Also, it is possible to introduce,
through the switching valve 85, a gas inert to the substrate
material and the conductive material, such as nitrogen, and
concurrently exhaust air through the exhaust valve 86 while
adjusting the pressure with a regulator 84, prior to the
depressurization before cleaning, as required. Further,
depressurization and drying can be performed after or during the
substitution of the nitrogen to fill the trenches with the
nitrogen, thereby enabling cleanly drying without oxidizing the
conductive material.
* * * * *